The Sed360 Test for Rapid Sand Particle Size Distribution Determination

Sed360 is a largely automated system for determining image-based particle size distributions (PSDs) of sands. A sedimented soil specimen contained in a 25.4-mm (1-in)-diameter circular acrylic tube sits atop a rotating stage. While the tube rotates, a camera captures an image of the specimen every 4 degrees of rotation. Narrow vertical strips from each image are automatically stitched together to form a complete, unwrapped 360 degrees view of the soil specimen. Image analysis based on a mathematical Haar wavelet transform generates the soil specimen's PSD. Three sands were tested with the Sed360 and the image-based PSDs are compared to traditional sieving results. As in earlier studies, very good agreement was observed. The Sed360 affords the same benefits of the system's predecessors (LabSed and FieldSed) over sieving but adds automatic image capture and stitching to create large 360 degrees unwrapped cylinder images of the specimen that are better suited for PSD determination by image analysis. The Sed360 also paves the way for testing a larger range of particle sizes by SedImaging.